title: SR-NLM: a sinogram restoration induced non-local means image filtering for low-dose computed tomography.
abstract: Radiation dose has raised significant concerns to patients and operators in modern X-ray computed tomography (CT) examinations. A simple and cost-effective means to perform a low-dose CT scan is to lower the milliampere-seconds (mAs) as low as reasonably achievable in data acquisition. However, the associated image quality with lower-mAs scans (or low-dose scans) will be unavoidably degraded due to the excessive data noise, if no adequate noise control is applied during image reconstruction. For image reconstruction with low-dose scans, sinogram restoration algorithms based on modeling the noise properties of measurement can produce an image with noise-induced artifact suppression, but they often suffer noticeable resolution loss. As an alternative technique, the noise-reduction algorithms via edge-preserving image filtering can yield an image without noticeable resolution loss, but they often do not completely eliminate the noise-induced artifacts. With above observations, in this paper, we present a sinogram restoration induced non-local means (SR-NLM) image filtering algorithm to retain the CT image quality by fully considering the advantages of the sinogram restoration and image filtering algorithms in low-dose image reconstruction. Extensive experimental results show that the present SR-NLM algorithm outperforms the existing methods in terms of cross profile, noise reduction, contrast-to-ratio measure, noise-resolution tradeoff and receiver operating characteristic (ROC) curves.
authors.affiliation: School of Biomedical Engineering, Southern Medical University, Guangdong, Guangzhou 510515, China.
authors.forename: Zhaoying
authors.initials: Z
authors.lastname: Bian
authors.forename: Jianhua
authors.initials: J
authors.lastname: Ma
authors.forename: Jing
authors.initials: J
authors.lastname: Huang
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.forename: Shanzhou
authors.initials: S
authors.lastname: Niu
authors.forename: Qianjin
authors.initials: Q
authors.lastname: Feng
authors.forename: Zhengrong
authors.initials: Z
authors.lastname: Liang
authors.forename: Wufan
authors.initials: W
authors.lastname: Chen
mesh_terms: D000465:Algorithms; D006801:Humans; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D013902:Radiography, Thoracic / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: CT; Image filtering; Low-dose; Non-local means; Sinogram restoration